Heart failure is one of the most significant causes of hospitalization, morbidity and mortality among elderly individuals in the United States. Research has demonstrated that patients with heart failure show cognitive impairment, which can impact functional abilities and quality of life. Medical interventions including implanted devices have led to improvements in symptom control and slowed progression of disease among patients with heart failure. Cardiac resynchronization therapy (CRT), a recently developed pacemaker based intervention, is associated with improvements on a range of cardiac functioning measures as well as enhanced health status and quality of life. However, no studies have examined cognitive functioning in this population, particularly in the context of change in cardiac functioning before and after CRT. In the present study, cardiac function and cognition will be examined among patients with heart failure before and after cardiac resynchronization therapy. This integration of cardiac and cognitive measures will help to elucidate the mechanisms by which cardiac disease is associated with cognitive decline, and will provide data on the effects of CRT on cognition.